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'lfilllitllti llIllllllT, 0T1" J'Ahftlfdilllt, BRITTFSH INDIA, ASfilIGNOIt UTE ONE-HALF T0 PEARY tllldlhlll'lll lUUTT, 0]? JABALPUR, nnrrrsrr INDIA.

lPldllGllilSS lfiflltt THE MANUFACTURE OF MAGNESIA.

To all whom it may concern: A

Be it known that l, Emu EDWARD DUTT, a subject of the King of Great Britain, residing at Jabalpur, in the Central Provinces of British lndia, have invented a new and lmproved'Pi-ocess for the Manufacture of Magnesia, of which the following is a clear, full, and exact description.

This invention relates to a process for the manufacture of magnesia from minerals, compounds or ores one of the ingredients of which is a compound of magnesium.

The object of the present invention is to manufacture magnesia from substances containing a magnesium compound, together with various other substanceaamong the principal of which may be mentioned the compounds of calcium.

To carry out the process containing magnesium is dissolved in hydrochloric acid, and a solution of magnesium and other chlorids is thereby obtained.

@ne'of the most suitable minerals for the purpose set forth in this specification is dolomite, which consists of a mixture of magnesium and calcium carbonates.

The solution of magnesium and calcium chloride obtained upon dissolving the dolomite in hydrochloric acid is decanted from any insoluble matter present, which consists of the silica and other insoluble impurities present in the raw materials used, and magnesium hydrate, or a mixture of magnesium hydrate and other alkaline earth hydrates or onids added in sufficient quantity to pre cipitate any iron that may be present in the solution, in the form of insoluble iron hydrate. The solution is then evaporated to dryness.

The mixture of magnesium and calcium chloride obtained, as described above, is placed in a retort or rotary furnace and subjected to the action of water vapor, at a temperature of from 450 to 700 C.

The water vapor reacts with the magnesium. chlorid, producing hydrochloric acid specification of ltetters Patent.

the substance Patented Dec. 23, 1919..

Application filed llctober it, 1.91%. ea-n1 No. 25ll,'708.

gas and magnesia, while the calcium chlorid remains 'unacted upon.

The hydrochloric acid gas is absorbed in water, when, it forms liquid hydrochloric acid. The latter is used over again in the process.

After reaction is complete, the mixture of magnesia andcalcium chlorid is dissolved in water, when the calcium chlorid being soluble, passes into solution, leaving behind the magnesia as an insoluble residue.

The magnesia is separated from the liquid, washed free from all chlorid, and

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evaporating the clear solution to dryness,

subjecting the resultant mixture of chloride to the action of steam at a temperature of from 4.50 to 700 (3., dissolving the calcium chlorid in water, and separating out the magnesia from the solution.

2. The herein described process for the manufacture of magnesia from magnesium compounds containing calcium and iron, which consists in treating the substance with hydrochloric acid, freeing the resultant solution from ironimpurities,evaporating it to dryness, heating the product at a temperature of about 450 to 7 00 (3., in the presence of steam, and separating the magnesia from the calcium chlorid.

lln testimony that l claim the foregoing as my invention 1 have signed my name this 22nd day of July 1918.

ERIC EDWARD BUTT. 

